Flexible display

ABSTRACT

The invention relates to a display device assembly ( 1 ) comprising a flexible display device ( 2 ) being rollable around an axis ( 5 ), the flexible display ( 2 ) having a front side ( 3 ) and a back side ( 4 ), one of the sides ( 3,4 ) being provided with distance elements ( 7, 7′,80 ) for preventing a direct contact between the front side ( 3 ) and the back side ( 4 ). By preventing the front and back side to contact each other the amount of display damage is significantly reduced as compared to conventional roll-up displays. An advantageous embodiment comprises a display device assembly in which the spacer elements are shaped in the form of bars ( 7, 7 ′). In a further advantageous embodiment of the display assembly the distance elements comprise a protection foil ( 80 ).

The invention is related to a display device assembly comprising aflexible display device being rollable around an axis, the flexibledisplay having a front and a back side.

US-2002/0070910 discloses a flexible display device assembly comprisinga flexible display device and a winding device to store the display in ahousing. A user of the display assembly pulls the display from thehousing to enjoy the content displayed on the display device. It is aproblem that the display device is sensitive to indentation, scratchingand tearing.

It is an aim of the invention to provide a display assembly in which thechance of damaging the display device is significantly reduced. To thisend the display device assembly according to the invention ischaracterized in that one of the sides is provided with distanceelements for preventing a direct contact between the front side and theback side.

The invention is based on the insight that damage to the conventionaldisplay is caused when the front and the back side of the display devicemake contact with each other. This happens during rolling-up of thedisplay, and when the display is in the rolled-up state and is moved ortransported. By preventing the front and back side to contact each otherthe amount of display damage is significantly reduced.

The dependent claims describe advantageous embodiments of the invention.

These and other objects of the invention will be apparent from andelucidated with reference to the embodiments described hereinafter.

In the drawings:

FIG. 1 shows an embodiment of the flexible display assembly according tothe invention,

FIGS. 2A-2D illustrate a few embodiments of hinge mechanisms,

FIG. 3 shows an embodiment of the invention wherein the distanceelements are provided with outer portions,

FIG. 4 shows a side view of the embodiment of FIG. 3,

FIG. 5 shows another embodiment wherein a back side of the bars isprovided with spacer blocks,

FIG. 6 shows a side view of the embodiment of FIG. 5, and

FIG. 7 shows an embodiment in which spacer blocks are provided withnotches for receiving the display,

FIG. 8 shows a side view of a further embodiment of the display assemblywherein the distance means comprise a protection foil,

FIG. 9 shows a side view of an embodiment in which the protection foilis stored,

FIG. 10 shows a side view of a further embodiment for storing theprotection foil.

The figures are not drawn to scale. In the figures, like referencenumerals generally refer to like parts.

Referring to FIG. 1, the display assembly according to the invention isshown. The display device assembly 1 comprises a flexible display device2 being rollable around an axis 5. The flexible display device 2, e.g.of the LCD type, has a front side 3 and a back side 4. Both sides 3,4comprise flexible sheets of plastic material. Due to its flexibility thedisplay is rollable. This property enables e.g. an easy storing of thedisplay assembly 1 when not in use. To prevent damage to the displaydevice 2 occurring during rolling-up and/or when the display is in therolled-up state, either the front side 3 or the back side 4 of thedisplay is provided with distance elements 7, 7′. In the example shownin FIG. 1 the back side 4 of the display is provided with such distanceelements, 7, 7′. Alternatively, distance means for preventing a directcontact between the front side 3 and the back side 4 may also beprovided in the form of a separate foil.

The distance elements 7,7′ prevent the occurrence of a direct contactbetween the front side 3 and the back side 4 of the display 2.Consequently, the amount of damage is significantly reduced as comparedto the conventional display.

In the example shown in FIG. 1 the distance elements comprise bars 7,7′, but the invention is not limited to this particular shape. Distanceelements 7, 7′ having the shape of bars and being positioned so as toinduce bending lines 8,8′ in the flexible display device that areoriented substantially parallel to the axis 5 have the advantage that avery effective protection against damage is obtained. Further, thedisplay may be easily rolled-up.

The bars 7, 7′ may be positioned against each other such that rolling ofthe flexible display device may occur in only one direction, i.e. thedirection necessary to roll it up indicated by the arrow 9. This easesthe rolling-up of the display and allows a one-hand operation. In theunrolled state the back side is rigid and firmly supports the display.

A further advantageous embodiment of the display assembly according tothe invention has bars 7, 7′ that comprise transparent material and aremounted on the front side 3. In this case the viewer sees the display 2through the bars, this is advantageous if positioning of the bars on theback side 4 is not possible or not preferred.

In FIG. 2A a hinge function is shown in the circle. FIG. 2B is anenlarged view of a first way of creating a hinge function between thesubsequent bars: in this example the hinge function is provided byadding a layer of a flexible material 21 that is positioned between thebars 7 and the back side 4 of the display. The additional flexible layer21 may be integrated with the flexible display itself. The flexiblelayer may comprise a, e.g., polyimide flexfoil containing electricallyconductive patterns. The flexible layer may be fixed to the displaydevice. The bars may contain electric or electronic components.

FIG. 2C shows an enlarged view of a second way of creating a hingefunction. In this case it is the material of the bars 7 itself which isflexible. The material is provided with grooves 23 that are orientedsubstantially parallel to the axis. At the location of the grooves theflexible material is able to provide a hinge function. Alternatively,real hinges between the bars are also option.

FIG. 2D shows that in order to limit the deformation of the materialduring bending, the contact between the bars 7, 7′and the display 2should preferably be limited to a center line 25, 25′ (displayed in FIG.2D as a single point, since the display is shown in side view) of thebars 7,7′.

A further advantageous embodiment of the display assembly is shown inFIG. 3. Here, a flexible display device assembly 1 has spacer elementswith outer portions 31, 31′. The outer portions 31, 31′ are providedwith spacer blocks 33, 33′ for creating a housing for storing theflexible display device when in the rolled-up state. Such a housingfurther protects the display against possible damage. To allow thedisplay to be rolled-up the spacer blocks have a taper.

FIG. 4 shows a side view of the embodiment shown in FIG. 3. The spacerblocks 33,33′ in combination with the bars 7, 7′ provide a protectivehousing for the display 2, when in the rolled-up state.

FIG. 5 shows an embodiment of the display device wherein the bars 7, 7′have aback side 51, and wherein spacer blocks 35,35′ are added to theback side 51 of the bars, resulting in a stiffer structure when thedisplay 2 is rolled out.

FIG. 6 provides a side view of the embodiment shown in FIG. 5 FIG. 7shows an embodiment of the display assembly according to the invention,wherein the bars 7 comprise spacer blocks 33, 33′ positioned at a sideopposite to the back side 51. The spacer blocks 33, 33′ have a displayside 73, 73′. The display side 73, 73′ of the spacer blocks 33, 33′ isprovided with notches 71, 71′ for receiving the flexible display device2. In this way the display 2 is loosely attached to the bars 7, 7′ andthere is no need to fix the display to a separate flexible layer.

Distance means comprising bars 7,7′ have the disadvantage that forobtaining a proper protection, the bars must have a sizeable thickness.However, in the case of rolling a display with a considerable lengththis will lead to a relatively thick roll.

FIG. 8 shows a preferable embodiment of the display assembly 1 whereinthe distance means comprise a protection foil 80.

In this embodiment the protection foil is rolled up together with thedisplay, thereby protecting the display surface in the rolled-up stateand during unrolling. When unrolled the protection film is placed behindthe display, where it supplies mechanical protection to the display.

The protection foil 80 preferably has a soft surface that touches thedisplay surface to protect damage of the front side 3. Due to itssoftness the foil embeds hard particles that otherwise might damage thedisplay surface by indentation and/or scratching.

To further improve the display assembly 1 it may be provided with ahousing 84 in which the assembly is stored when not in use. The housingreduces the vulnerability with respect to damage of the assembly whenbeing in the rolled-up state.

The protection foil 80 is rolled-up together with the display, and italso unrolls with the display when this is unrolled for use. Since thefront side 3 of the display needs to be uncovered when the assembly isunrolled, the unrolled protection foil 9 has to be stored. One option isshown in FIG. 8, where the protection film, being connected to a rim ofthe backside of the display, after leaving the housing 84 is returnedinto the housing via a cylindrically shaped element that guides theprotection foil 80. The protection foil is subsequently wound around thepart of the display that is inside the housing 84. This embodiment hasthe advantage that no additional storage means for the protection foil80 are needed.

Alternatively, the protection foil 80 may be rolled-up in the samehousing 84 that houses the display assembly 1. To enable this eithersome extra space needs to be reserved within the housing (FIG. 9). Or anadditional degree of freedom for allowing a translational movement ofcylindrically shaped elements on which the foil and display are wound86,88, inside the housing may be introduced (FIG. 10). In the latterembodiment, the cylinder 88 around which the display is rolled, moveswith respect to the housing (in the direction indicated by the arrows)when the length of the display stored on the cylinder decreases. Thusmore space is created for rolling the protection film on the storagecylinder 86.

In summary, the invention relates to a display device assembly 1comprising a flexible display device 2 being rollable around an axis 5,the flexible display 2 having a front side 3 and a back side 4, one ofthe sides being provided with distance elements 7, 7′, 80 for preventinga direct contact between the front side 3 and the back side 4. Bypreventing the front and back side to contact each other the amount ofdisplay damage is significantly reduced as compared to conventionalroll-up displays. An advantageous embodiment comprises a display deviceassembly in which the distance elements are shaped in the form of bars7, 7′. In a further advantageous embodiment of the display assembly thedistance elements comprise a protection foil 80.

It should be noted that the above-mentioned embodiments illustraterather than limit the invention, and that those skilled in the art willbe able to design many alternative embodiments without departing fromthe scope of the appended claims. In the claims, any reference signsplaced between parentheses shall not be construed as limiting the claim.The word “comprising” does not exclude the presence of other elements orsteps than those listed in a claim. The word “a” or “an” preceding anelement does not exclude the presence of a plurality of such elements.

1. A display device assembly (1) comprising a flexible display device(2) being rollable around an axis (5), the flexible display having afront side (3) and a back side (4), one of the sides (3,4) beingprovided with distance means (7, 7′, . . . ) for preventing a directcontact between the front side (3) and the back side (4).
 2. A flexibledisplay device assembly according to claim 1, wherein the distance meanscomprise bars (7,7′, . . . ), which are positioned so as to inducebending lines (8,8′,8″, . . .) in the flexible display device that areoriented substantially parallel to the axis (5).
 3. A flexible displaydevice assembly according to claim 2, wherein the bars (7,7′, . . . )comprise transparent material and are mounted on the front side (3) ofthe flexible display (2).
 4. A flexible display device assemblyaccording to claim 2, wherein the bars (7, 7′, . . . ) are positionedagainst each other, such that rolling of the flexible display device mayoccur in only one direction (9).
 5. A flexible display device assemblyaccording to claim 2, wherein the flexible display device is furtherprovided with a layer of flexible material (21) that is positionedbetween the bars (7,7′, . . . ) and the back side (4) of the display. 6.A flexible display device assembly according to claim 2, wherein thebars (7,7′, . . . ) are provided to the display in the form of a pieceof material having grooves (23) that are oriented substantially parallelto the axis (5).
 7. A flexible display device assembly according toclaim 2, wherein outer portions (31,31′, . . . ) of the spacer elements(7,7′, . . . ) are provided with spacer blocks (33,33′, . . . ) forcreating a housing for the flexible display device in the rolled-upstate.
 8. A flexible display device assembly according to claim 2,wherein blocks (35,35′, . . . ) are positioned on aback side (51) of thebars (7,7′, . . . ).
 9. A flexible display device assembly according toclaim 7, wherein each spacer block (33,33′, . . . ) has a display side(73,73′, . . . ) that is provided with a notch (71,71′, . . . ) forreceiving the flexible display device (2).
 10. A flexible display deviceassembly according to claim 1, wherein the distance means comprise aprotection foil (80).
 11. A flexible display assembly according to claim10, wherein the display assembly further comprises guiding means (82)for guiding the protection foil (80) when the assembly (1) is beingrolled into the unrolled state, such that the front side (3) of thedisplay is not covered by the protection foil (80).
 12. A flexibledisplay assembly according to claim 11, wherein the protection foil (80)is connected to the back side (4) of the display.
 13. A flexible displayassembly according to claim 11, wherein the display assembly is furtherprovided with storing means (86) for storing the protection foil (80),when the display is in the unrolled state.
 14. A flexible displayassembly according to claim 13, wherein the storing means comprise acylindrically shaped element (86) for winding the protection foilaround.
 15. A flexible display assembly according to claim 13, whereinthe storing means (86) is arranged to enable a translational movementwith respect to the housing (84).
 16. A flexible display assemblyaccording to claim 11, wherein the assembly is provided with acylindrically shaped element for winding the display around (88), saidcylindrically shaped element being arranged to be translatable withrespect to the housing (84).